Radio frequency energy-transmitting apparatus with location detection function and radio frequency energy-harvesting apparatus and radio frequency energy-transmitting method with location detection function

ABSTRACT

A radio frequency energy-transmitting apparatus includes a harmonic radar unit and a harmonic radar control unit. The harmonic radar unit transmits a radar wave with a fundamental frequency. After a radio frequency energy-harvesting apparatus receives the radar wave, the radio frequency energy-harvesting apparatus generates and transmits a radar reflection harmonic wave. A frequency of the radar reflection harmonic wave is a multiple frequency of the radar wave. After the harmonic radar unit receives the radar reflection harmonic wave, the harmonic radar control unit determines a location of the radio frequency energy-harvesting apparatus. According to the location of the radio frequency energy-harvesting apparatus, the harmonic radar control unit controls the harmonic radar unit, so that a radar wave beam of the radar wave transmitted from the harmonic radar unit is directed toward the location of the radio frequency energy-harvesting apparatus.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an energy-transmitting apparatus, anenergy-harvesting apparatus and an energy-transmitting method, andespecially relates to a radio frequency energy-transmitting apparatuswith a location detection function, a radio frequency energy-harvestingapparatus and a radio frequency energy-transmitting method with thelocation detection function.

Description of the Related Art

The related art wireless signal energy-harvesting system at least hasfollowing disadvantages:

1. The wireless signals transmitted by most of the related art radiofrequency energy-transmitting apparatuses (for examples, the radio ortelecom base station) is omnidirectional, so that the energy density atthe location of the related art radio frequency energy-harvestingapparatus is possibly not high enough, so that the conversion efficiencyof the related art radio frequency energy-harvesting apparatus is low.

2. The wireless signal transmitted by some of the related art radiofrequency energy-transmitting apparatuses is directional to the locationof the related art radio frequency energy-harvesting apparatus, but thelocation indicator component with higher power consumption has to bearranged in the related art radio frequency energy-harvesting apparatus.For example, locating the related art radio frequency energy-harvestingapparatus can be achieved by the GPS, Beacon or Wi-Fi communicationcomponents. However, the location indicator component with higher powerconsumption does not accord with the spirit of the energy-harvestingapparatus.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, the first object of thepresent invention is to provide a radio frequency energy-transmittingapparatus with a location detection function.

In order to solve the above-mentioned problems, the second object of thepresent invention is to provide a radio frequency energy-harvestingapparatus.

In order to solve the above-mentioned problems, the third object of thepresent invention is to provide a radio frequency energy-transmittingmethod with the location detection function

In order to achieve the first object of the present invention mentionedabove, the radio frequency energy-transmitting apparatus is applied to aradio frequency energy-harvesting apparatus. The radio frequencyenergy-transmitting apparatus comprises a harmonic radar unit and aharmonic radar control unit electrically connected to the harmonic radarunit. The harmonic radar unit transmits a radar wave scanning to aspace. After the radio frequency energy-harvesting apparatus receivesthe radar wave, according to the radar wave, the radio frequencyenergy-harvesting apparatus generates a radar reflection harmonic wave.A frequency of the radar reflection harmonic wave is different from afrequency of the radar wave. The radio frequency energy-harvestingapparatus transmits the radar reflection harmonic wave. After theharmonic radar unit receives the radar reflection harmonic wave,according to the radar reflection harmonic wave, the harmonic radarcontrol unit determines a location of the radio frequencyenergy-harvesting apparatus. According to the location of the radiofrequency energy-harvesting apparatus, the harmonic radar control unitcontrols the harmonic radar unit, so that a radar wave beam of the radarwave transmitted from the harmonic radar unit is directed toward thelocation of the radio frequency energy-harvesting apparatus.

Moreover, the frequency of the radar reflection harmonic wave is anintegral multiple frequency of the radar wave.

Moreover, the frequency of the radar reflection harmonic wave is adouble frequency of the radar wave.

Moreover, the radio frequency energy-transmitting apparatus is furtherapplied to a power source. The harmonic radar unit comprises a powerdivider, a switchable phase delay module and an antenna array. The powerdivider is electrically connected to the power source. The switchablephase delay module is electrically connected to the power divider andthe harmonic radar control unit. The antenna array is electricallyconnected to the switchable phase delay module. The power sourcetransmits a power to the power divider. The power divider splits thepower into some equal parts and transmits the equal power to eachindividual delay path in the switchable phase delay module. According tothe location of the radio frequency energy-harvesting apparatus, theharmonic radar control unit controls the switchable phase delay moduleto control a phase of the power, so that the radar wave beam of theradar wave transmitted from the antenna array is directed toward thelocation of the radio frequency energy-harvesting apparatus.

Moreover, the harmonic radar control unit comprises a harmonic radarcontrol circuit and a location determination circuit. The harmonic radarcontrol circuit is electrically connected to the switchable phase delaymodule. The location determination circuit is electrically connected tothe harmonic radar control circuit. The harmonic radar unit furthercomprises a harmonic receiving antenna and a harmonic power detectorelectrically connected to the harmonic receiving antenna and thelocation determination circuit. After the location determination circuitreceives the radar reflection harmonic wave through the harmonicreceiving antenna and the harmonic power detector, according to acomparative result between an intensity of the radar reflection harmonicwave and an intensity of a background harmonic noise, the locationdetermination circuit determines whether the radio frequencyenergy-harvesting apparatus exists or not, to generate a location signalrelated with the location of the radio frequency energy-harvestingapparatus. The location determination circuit transmits the locationsignal to the harmonic radar control circuit.

Moreover, the harmonic radar control unit controls the switchable phasedelay module by an analog modulation control mode.

In order to achieve the second object of the present invention mentionedabove, the radio frequency energy-harvesting apparatus is applied to aradio frequency energy-transmitting apparatus with a location detectionfunction. The radio frequency energy-harvesting apparatus comprises adirect current signal receiving-processing unit, a rectification andharmonic generation unit and a radar wave receiving-transmitting unit.The rectification and harmonic generation unit is electrically connectedto the direct current signal receiving-processing unit. The radar wavereceiving-transmitting unit is electrically connected to therectification and harmonic generation unit. The radio frequencyenergy-transmitting apparatus transmits a radar wave scanning to aspace. After the radar wave receiving-transmitting unit receives theradar wave, according to the radar wave, the radar wavereceiving-transmitting unit generates an alternating current signal. Theradar wave receiving-transmitting unit transmits the alternating currentsignal to the rectification and harmonic generation unit. Therectification and harmonic generation unit generates a radar reflectionharmonic wave and a direct current signal. A frequency of the radarreflection harmonic wave is different from a frequency of the radarwave. The rectification and harmonic generation unit transmits the radarreflection harmonic wave to the radio frequency energy-transmittingapparatus through the radar wave receiving-transmitting unit. Therectification and harmonic generation unit transmits the direct currentsignal to the direct current signal receiving-processing unit.

Moreover, the frequency of the radar reflection harmonic wave is anintegral multiple frequency of the radar wave.

Moreover, the frequency of the radar reflection harmonic wave is adouble frequency of the radar wave.

Moreover, the radar wave receiving-transmitting unit comprises amatching circuit electrically connected to the rectification andharmonic generation unit. After the radar wave receiving-transmittingunit receives the radar wave, according to the radar wave, the matchingcircuit processes the radar wave by a matching process to generate thealternating current signal. The matching circuit transmits thealternating current signal to the rectification and harmonic generationunit.

Moreover, the radar wave receiving-transmitting unit further comprises afirst selection switch and a second selection switch. The firstselection switch is electrically connected to the matching circuit. Thesecond selection switch is electrically connected to the matchingcircuit and the rectification and harmonic generation unit.

Moreover, the matching circuit comprises a harmonic optimizationmatching sub-circuit and an energy-harvesting optimization matchingsub-circuit. The harmonic optimization matching sub-circuit iselectrically connected to the first selection switch and the secondselection switch. The energy-harvesting optimization matchingsub-circuit is electrically connected to the first selection switch andthe second selection switch. If the direct current signal is less than apredetermined value, the first selection switch and the second selectionswitch are controlled, so that the harmonic optimization matchingsub-circuit receives the radar wave. If the direct current signal isgreater than or equal to the predetermined value, the first selectionswitch and the second selection switch are controlled, so that theenergy-harvesting optimization matching sub-circuit receives the radarwave.

Moreover, the radar wave receiving-transmitting unit further comprises aradar wave receiving antenna and a harmonic transmitting antenna. Theradar wave receiving antenna is electrically connected to the firstselection switch. The harmonic transmitting antenna is electricallyconnected to the second selection switch and the rectification andharmonic generation unit. The radar wave receiving antenna receives theradar wave and transmits the radar wave to the matching circuit throughthe first selection switch. The rectification and harmonic generationunit transmits the radar reflection harmonic wave to the radio frequencyenergy-transmitting apparatus through the harmonic transmitting antenna.

Moreover, the rectification and harmonic generation unit is a bridgerectifier.

Moreover, the radio frequency energy-harvesting apparatus furthercomprises a low pass filter and a selection switch controller. The lowpass filter is electrically connected to the rectification and harmonicgeneration unit and the direct current signal receiving-processing unit.The selection switch controller is electrically connected to the lowpass filter, the first selection switch and the second selection switch.The selection switch controller controls the first selection switch andthe second selection switch.

Moreover, the radar wave receiving antenna and the harmonic transmittingantenna can be integrated as a dual-mode antenna electrically connectedto the first selection switch.

In order to achieve the third object of the present invention mentionedabove, the radio frequency energy-transmitting method comprisesfollowing steps. A harmonic radar unit transmits a radar wave scanningto a space. After a radio frequency energy-harvesting apparatus receivesthe radar wave, according to the radar wave, the radio frequencyenergy-harvesting apparatus generates a radar reflection harmonic wave.A frequency of the radar reflection harmonic wave is different from afrequency of the radar wave. The radio frequency energy-harvestingapparatus transmits the radar reflection harmonic wave. After theharmonic radar unit receives the radar reflection harmonic wave,according to the radar reflection harmonic wave, a harmonic radarcontrol unit determines the location of the radio frequencyenergy-harvesting apparatus. According to the location of the radiofrequency energy-harvesting apparatus, the harmonic radar control unitcontrols the harmonic radar unit, so that a radar wave beam of the radarwave transmitted from the harmonic radar unit is directed toward thelocation of the radio frequency energy-harvesting apparatus.

Moreover, the frequency of the radar reflection harmonic wave is anintegral multiple frequency of the radar wave.

Moreover, the harmonic radar unit scans and records a set of powerintensities data of a plurality of radar reflected harmonic waves. Ifthe power intensity of the radar reflected harmonic wave is greater thana background harmonic power intensity a power predetermined value (forexample, 3 dBm), the harmonic radar unit determines that the radarelectric wave is the radar reflection harmonic wave.

Moreover, if the power intensity of the radar reflected harmonic wave isnot greater than the background harmonic power intensity the powerpredetermined value, the harmonic radar unit determines that the radarreflected harmonic wave is not the radar reflection harmonic wave, andthen the harmonic radar unit neglect the radar reflected harmonic wave.

The present invention has at least following advantages:

1. The radar wave beam of the radar wave transmitted from the radiofrequency energy-transmitting apparatus is directed toward the locationof the radio frequency energy-harvesting apparatus, so that the energydensity of the location of the radio frequency energy-harvestingapparatus is higher, so that the radio frequency energy-harvestingapparatus obtains higher energy.

2. According to the concept of the radar reflection harmonic wave, theradio frequency energy-transmitting apparatus can detect the location ofthe radio frequency energy-harvesting apparatus easily, so that thecircuit structure of the radio frequency energy-harvesting apparatus issimple and energy is saved to accord with the concept of theenergy-harvesting apparatus. The present invention does not need theGPS, Beacon or Wi-Fi communication components to locate the radiofrequency energy-harvesting apparatus.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 shows a block diagram of the radio frequency energy-transmittingapparatus and the radio frequency energy-harvesting apparatus of thepresent invention.

FIG. 2 shows a block diagram of an embodiment of the radio frequencyenergy-transmitting apparatus of the present invention.

FIG. 3 shows a block diagram of an embodiment of the radio frequencyenergy-harvesting apparatus of the present invention.

FIG. 4 shows a flow chart of the radio frequency energy-transmittingmethod of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Please refer to following detailed description and figures for thetechnical content of the present invention. The following detaileddescription and figures are referred for the present invention, but thepresent invention is not limited to it.

FIG. 1 shows a block diagram of the radio frequency energy-transmittingapparatus and the radio frequency energy-harvesting apparatus of thepresent invention. A radio frequency energy-transmitting apparatus 10with a location detection function is applied to a radio frequencyenergy-harvesting apparatus 20 and a power source 50. The radiofrequency energy-transmitting apparatus 10 comprises a harmonic radarunit 30 and a harmonic radar control unit 60. The harmonic radar unit 30comprises a power divider 306, a switchable phase delay module 308, anantenna array 310, a harmonic receiving antenna 312 and a harmonic powerdetector 314. The harmonic radar control unit 60 comprises a harmonicradar control circuit 40 and a location determination circuit 316.

The harmonic radar control unit 60 is electrically connected to theharmonic radar unit 30. The power divider 306 is electrically connectedto the power source 50. The switchable phase delay module 308 iselectrically connected to the power divider 306 and the harmonic radarcontrol unit 60. The antenna array 310 is electrically connected to theswitchable phase delay module 308. The harmonic power detector 314 iselectrically connected to the harmonic receiving antenna 312. Thelocation determination circuit 316 is electrically connected to theharmonic power detector 314 and the harmonic radar control circuit 40.

The harmonic radar unit 30 transmits a radar wave 302 scanning to aspace. After the radio frequency energy-harvesting apparatus 20 receivesthe radar wave 302, according to the radar wave 302, the radio frequencyenergy-harvesting apparatus 20 generates a radar reflection harmonicwave 202. A frequency of the radar reflection harmonic wave 202 isdifferent from a frequency of the radar wave 302. For example, thefrequency of the radar reflection harmonic wave 202 is an integralmultiple frequency of the radar wave 302. For another example, thefrequency of the radar reflection harmonic wave 202 is a doublefrequency of the radar wave 302 (for example, the frequency of the radarwave 302 is 915 MHz, and the frequency of the radar reflection harmonicwave 202 is 1830 MHz).

The radio frequency energy-harvesting apparatus 20 transmits the radarreflection harmonic wave 202. After the harmonic radar unit 30 receivesthe radar reflection harmonic wave 202, according to a comparativeresult between an intensity of the radar reflection harmonic wave 202and an intensity of a background harmonic noise, the harmonic radarcontrol unit 60 determines a location of the radio frequencyenergy-harvesting apparatus 20. According to the location of the radiofrequency energy-harvesting apparatus 20, the harmonic radar controlunit 60 controls the harmonic radar unit 30, so that a radar wave beamof the radar wave 302 transmitted from the harmonic radar unit 30 isdirected toward the location of the radio frequency energy-harvestingapparatus 20.

The power source 50 transmits a power 52 to the power divider 306. Thepower divider 306 transmits the power 52 to the switchable phase delaymodule 308 evenly and distributively. According to the location of theradio frequency energy-harvesting apparatus 20, the harmonic radarcontrol unit 40 controls the switchable phase delay module 308 tocontrol a phase of the power 52, so that the radar wave beam of theradar wave 302 transmitted from the antenna array 310 is directed towardthe location of the radio frequency energy-harvesting apparatus 20. Inanother word, different phase delay signal feeding into the antenna willform different antenna array pattern. After designing, the radiationdirection of the antenna can be changed. The harmonic radar controlcircuit 40 controls the switchable phase delay module 308 to control theantenna array 310 by some logic circuits (not shown in FIG. 1).

After the location determination circuit 316 receives the radarreflection harmonic wave 202 through the harmonic receiving antenna 312and the harmonic power detector 314, according to a comparative resultbetween the intensity of the radar reflection harmonic wave 202 and theintensity of the background harmonic noise, the location determinationcircuit 316 determines whether the radio frequency energy-harvestingapparatus 20 exists or not, to generate a location signal 304 relatedwith the location of the radio frequency energy-harvesting apparatus 20.The location determination circuit 316 transmits the location signal 304to the harmonic radar control circuit 40. The location determinationcircuit 316 is, for example but not limited to, a signal processing unitcircuit.

FIG. 2 shows a block diagram of an embodiment of the radio frequencyenergy-transmitting apparatus of the present invention. Besides thecomponents shown in FIG. 1, the harmonic radar unit 30 further comprisesa power amplifier 318 and a first filter 326. The switchable phase delaymodule 308 comprises a plurality of switch units 320 and a plurality ofphase delay units 322. The antenna array 310 comprises a plurality ofantenna units 324. The harmonic power detector 314 comprises anamplifier 328, a second filter 330 (such as a low pass filter) and ananalog to digital converter 332.

The harmonic radar control circuit 40 controls the switch units 320, sothat the phase delay units 322 are turned on or turned off, so that theradar wave beam of the radar wave 302 transmitted from the antenna unit324 is directed toward the location of the radio frequencyenergy-harvesting apparatus 20.

The antenna array 310 can be arranged one-dimensionally ortwo-dimensionally. In the embodiment show in FIG. 2, the antenna array310 is a 2×2 antenna array. According to the switch units 320 and thephase delay units 322, the phase angle can be the phase delay of 0degree, +90 degrees or −90 degrees, so that the 2×2 antenna array cangenerate the radar wave beam with different directions which aredetermined by the radar reflection harmonic wave 202 of the radiofrequency energy-harvesting apparatus 20.

The harmonic radar control unit 60 (or the harmonic radar controlcircuit 40) controls the switchable phase delay module 308 by a digitalmodulation control mode. Or when the harmonic radar control unit 60 (orthe harmonic radar control circuit 40) is an analog modulation controlmode unit, the switchable phase delay module 308 is an analogcontinuously variable phase delay module. The harmonic radar controlunit 60 (or the harmonic radar control circuit 40) controls theswitchable phase delay module 308 by an analog modulation control mode.

Please refer to FIG. 1 again. The radio frequency energy-harvestingapparatus 20 is applied to the radio frequency energy-transmittingapparatus 10. The radio frequency energy-harvesting apparatus 20comprises a direct current signal receiving-processing unit 204, arectification and harmonic generation unit 206 and a radar wavereceiving-transmitting unit 208. The rectification and harmonicgeneration unit 206 is electrically connected to the direct currentsignal receiving-processing unit 204. The radar wavereceiving-transmitting unit 208 is electrically connected to therectification and harmonic generation unit 206.

The radio frequency energy-transmitting apparatus 10 transmits the radarwave 302 scanning to the space. After the radar wavereceiving-transmitting unit 208 receives the radar wave 302, accordingto the radar wave 302, the radar wave receiving-transmitting unit 208generates an alternating current signal 210. The radar wavereceiving-transmitting unit 208 transmits the alternating current signal210 to the rectification and harmonic generation unit 206.

After the rectification and harmonic generation unit 206 receives thealternating current signal 210, according to the alternating currentsignal 210, the rectification and harmonic generation unit 206 generatesa harmonic signal 232 and a direct current signal 212. The rectificationand harmonic generation unit 206 transmits the harmonic signal 232 tothe radar wave receiving-transmitting unit 208. According to theharmonic signal 232, the radar wave receiving-transmitting unit 208generates and transmits the radar reflection harmonic wave 202 to theradio frequency energy-transmitting apparatus 10. The rectification andharmonic generation unit 206 transmits the direct current signal 212 tothe direct current signal receiving-processing unit 204. After thedirect current signal receiving-processing unit 204 receives the directcurrent signal 212, a backend application apparatus (not shown inFIG. 1) utilizes the energy of the direct current signal 212. This isthe concept of the energy-harvesting apparatus.

FIG. 3 shows a block diagram of an embodiment of the radio frequencyenergy-harvesting apparatus of the present invention. Besides thecomponents shown in FIG. 1, the radio frequency energy-harvestingapparatus 20 further comprises a low pass filter 228 and a selectionswitch controller 230. The radar wave receiving-transmitting unit 208comprises a matching circuit 214, a first selection switch 216, a secondselection switch 218, a radar wave receiving antenna 224 and a harmonictransmitting antenna 226. The matching circuit 214 comprises a harmonicoptimization matching sub-circuit 220 and an energy-harvestingoptimization matching sub-circuit 222.

The low pass filter 228 is electrically connected to the rectificationand harmonic generation unit 206 and the direct current signalreceiving-processing unit 204. The selection switch controller 230 iselectrically connected to the low pass filter 228, the first selectionswitch 216 and the second selection switch 218. The matching circuit 214is electrically connected to the rectification and harmonic generationunit 206. The first selection switch 216 is electrically connected tothe matching circuit 214. The second selection switch 218 iselectrically connected to the matching circuit 214 and the rectificationand harmonic generation unit 206. The radar wave receiving antenna 224is electrically connected to the first selection switch 216. Theharmonic transmitting antenna 226 is electrically connected to thesecond selection switch 218 and the rectification and harmonicgeneration unit 206. The harmonic optimization matching sub-circuit 220is electrically connected to the first selection switch 216 and thesecond selection switch 218. The energy-harvesting optimization matchingsub-circuit 222 is electrically connected to the first selection switch216 and the second selection switch 218.

After the radar wave receiving-transmitting unit 208 receives the radarwave 302, according to the radar wave 302, the matching circuit 214processes the radar wave 302 by a matching process to generate thealternating current signal 210. The matching circuit 214 transmits thealternating current signal 210 to the rectification and harmonicgeneration unit 206.

In an embodiment, if the direct current signal 212 is less than apredetermined value, the first selection switch 216 and the secondselection switch 218 are controlled (to connect upwards), so that theharmonic optimization matching sub-circuit 220 receives the radar wave302. If the direct current signal 212 is greater than or equal to thepredetermined value, the first selection switch 216 and the secondselection switch 218 are controlled (to connect downwards), so that theenergy-harvesting optimization matching sub-circuit 222 receives theradar wave 302.

In another word, in the very beginning, the harmonic optimizationmatching sub-circuit 220 (for example, having greater reflectioncoefficient) is utilized, so that the rectification and harmonicgeneration unit 206 generates better radar reflection harmonic wave 202(namely, can be identified and detected by the radio frequencyenergy-transmitting apparatus 10 more easily). After that, theenergy-harvesting optimization matching sub-circuit 222 is utilized, sothat the rectification and harmonic generation unit 206 has betteralternating current to direct current conversion efficiency.

The radar wave receiving antenna 224 receives the radar wave 302 andtransmits the radar wave 302 to the matching circuit 214 through thefirst selection switch 216. The rectification and harmonic generationunit 206 transmits the harmonic signal 232 to the harmonic transmittingantenna 226. According to the harmonic signal 232, the harmonictransmitting antenna 226 generates and transmits the radar reflectionharmonic wave 202 to the radio frequency energy-transmitting apparatus10. The selection switch controller 230 controls the first selectionswitch 216 and the second selection switch 218.

When the electromagnetic wave touches different interfaces, thereflected wave is generated. The strength of the reflected wave isrelated with the antenna radiation and the reflection coefficient of theinterface. The rectification and harmonic generation unit 206 is, forexample but not limited to, a bridge rectifier. When different dioderectification circuit receives the electromagnetic wave, differentharmonic waves will be generated by different diode rectificationcircuits, and then the harmonic waves will be reflected to the spacethrough the antenna.

Please refer to FIG. 1 at the same time. The energy of the secondharmonic reflected to the space is determined by the nonlinearrectification characteristics of the diode and the radiation efficiencyof the original receiving antenna (namely, the radar wave receivingantenna 224). Utilizing the harmonic wave transmitted to the space bythe rectification and harmonic generation unit 206 of the radiofrequency energy-harvesting apparatus 20, the radio frequencyenergy-harvesting apparatus 20 can be deemed as a harmonic signalsource, wherein the strength of the harmonic signal source is thegreatest when the radar wave beam of the radar wave 302 transmitted fromthe antenna array 310 is directed toward the location of the radiofrequency energy-harvesting apparatus 20.

Therefore, according to the concept of the radar, if the radar wave beamof the radar wave 302 does not scan the radio frequencyenergy-harvesting apparatus 20, the energy of the harmonic wave receivedby the harmonic receiving antenna 312 of the radio frequencyenergy-transmitting apparatus 10 is the lowest (background noise).Conversely, if the radar wave beam of the radar wave 302 just scans theradio frequency energy-harvesting apparatus 20, the energy of theharmonic wave received by the harmonic receiving antenna 312 of theradio frequency energy-transmitting apparatus 10 is the greatest.

The radar wave receiving antenna 224 and the harmonic transmittingantenna 226 can be, for example but not limited to, integrated as adual-mode antenna (or dual-frequency antenna, such as a yagi antenna).Moreover, the rectification and harmonic generation unit 206 and theradar wave receiving-transmitting unit 208 can be, for example but notlimited to, integrated as a rectenna.

FIG. 4 shows a flow chart of the radio frequency energy-transmittingmethod of the present invention. The radio frequency energy-transmittingmethod at least comprises following steps.

S02: A harmonic radar unit transmits a radar wave scanning to a space.

S04: After a radio frequency energy-harvesting apparatus receives theradar wave, according to the radar wave, the radio frequencyenergy-harvesting apparatus generates a radar reflection harmonic wave.

S06: The radio frequency energy-harvesting apparatus transmits the radarreflection harmonic wave.

S08: After the harmonic radar unit receives the radar reflectionharmonic wave, according to the radar reflection harmonic wave, aharmonic radar control unit determines a location of the radio frequencyenergy-harvesting apparatus.

S10: According to the location of the radio frequency energy-harvestingapparatus, the harmonic radar control unit controls the harmonic radarunit, so that a radar wave beam of the radar wave transmitted from theharmonic radar unit is directed toward the location of the radiofrequency energy-harvesting apparatus.

A frequency of the radar reflection harmonic wave is different from afrequency of the radar wave. For example, the frequency of the radarreflection harmonic wave is an integral multiple frequency of the radarwave. For another example, the frequency of the radar reflectionharmonic wave is a double frequency of the radar wave.

Moreover, in the step S08, the harmonic radar unit scans and recordspower intensities of a plurality of radar electric waves. If the powerintensity of the radar electric wave is greater than a backgroundharmonic power intensity a power predetermined value (for example, 3dBm), the harmonic radar unit determines that the radar electric wave isthe radar reflection harmonic wave. If the power intensity of the radarelectric wave is not greater than the background harmonic powerintensity the power predetermined value, the harmonic radar unitdetermines that the radar electric wave is not the radar reflectionharmonic wave, and then the harmonic radar unit eliminates the radarelectric wave. The power predetermined value can be set. Moreover, theharmonic radar unit scans the space, records the power intensities ofthe reflected harmonic waves which are received, and records the phasedelay module setting values, and then follows the steps mentioned aboveto detect the location of the radio frequency energy-harvestingapparatus.

Moreover, in another embodiment, plural radio frequencyenergy-harvesting apparatuses are located in the space at the same time.At this time, the power predetermined value can be set, so that theradar wave beam of the radar wave transmitted from the harmonic radarunit is directed toward the locations of the radio frequencyenergy-harvesting apparatuses, wherein the power intensities of theradar electric waves transmitted from the radio frequencyenergy-harvesting apparatuses are greater than the background harmonicpower intensity the power predetermined value.

The nonlinear harmonic components of the harmonic radar unit may leakout to the harmonic receiving antenna 312 as shown in FIG. 1. This iscalled the background harmonic noise. The radar electric waves mayinclude the background harmonic noise, the radar reflection harmonicwave and other reflected waves from other objects. However, thebackground harmonic noise and the other reflected waves from otherobjects have to be eliminated. Only the radar reflection harmonic wavecan provide the location information of the radio frequencyenergy-harvesting apparatus.

The other content of the radio frequency energy-transmitting method ofthe present invention is similar to those shown in FIGS. 1-3, so that itis not repeated here for brevity. Moreover, please refer to FIG. 1again. The radio frequency energy-transmitting apparatus 10 added by theradio frequency energy-harvesting apparatus 20 can be named as a radiofrequency energy-transmitting system with the location detectionfunction.

The present invention has at least following advantages:

1. The radar wave beam of the radar wave transmitted from the radiofrequency energy-transmitting apparatus is directed toward the locationof the radio frequency energy-harvesting apparatus, so that the energydensity of the location of the radio frequency energy-harvestingapparatus is higher, so that the radio frequency energy-harvestingapparatus obtains higher energy.

2. According to the concept of the radar reflection harmonic wave, theradio frequency energy-transmitting apparatus can detect the location ofthe radio frequency energy-harvesting apparatus easily, so that thecircuit structure of the radio frequency energy-harvesting apparatus issimple and energy is saved to accord with the concept of theenergy-harvesting apparatus. The present invention does not need theGPS, Beacon or Wi-Fi communication components to locate the radiofrequency energy-harvesting apparatus.

Although the present invention has been described with reference to thepreferred embodiment thereof, it will be understood that the inventionis not limited to the details thereof. Various substitutions andmodifications have been suggested in the foregoing description, andothers will occur to those of ordinary skill in the art. Therefore, allsuch substitutions and modifications are intended to be embraced withinthe scope of the invention as defined in the appended claims.

What is claimed is:
 1. A radio frequency energy-transmitting apparatusapplied to a radio frequency energy-harvesting apparatus, the radiofrequency energy-transmitting apparatus comprising: a harmonic radarunit; and a harmonic radar control circuit electrically connected to theharmonic radar unit, wherein the harmonic radar unit transmits a radarwave scanning to a space; after the radio frequency energy-harvestingapparatus receives the radar wave, according to the radar wave, theradio frequency energy-harvesting apparatus generates a radar reflectionharmonic wave; a frequency of the radar reflection harmonic wave isdifferent from a frequency of the radar wave; the radio frequencyenergy-harvesting apparatus transmits the radar reflection harmonicwave; after the harmonic radar unit receives the radar reflectionharmonic wave, according to the radar reflection harmonic wave, theharmonic radar control unit determines a location of the radio frequencyenergy-harvesting apparatus; according to the location of the radiofrequency energy-harvesting apparatus, the harmonic radar control unitcontrols the harmonic radar unit, so that a radar wave beam of the radarwave transmitted from the harmonic radar unit is directed toward thelocation of the radio frequency energy-harvesting apparatus.
 2. Theradio frequency energy-transmitting apparatus in claim 1, wherein thefrequency of the radar reflection harmonic wave is an integral multiplefrequency of the radar wave.
 3. The radio frequency energy-transmittingapparatus in claim 2, wherein the frequency of the radar reflectionharmonic wave is a double frequency of the radar wave.
 4. The radiofrequency energy-transmitting apparatus in claim 3 further applied to apower source, wherein the harmonic radar unit comprises: a power dividerelectrically connected to the power source; a switchable phase delaymodule electrically connected to the power divider and the harmonicradar control unit; and an antenna array electrically connected to theswitchable phase delay module, wherein the power source transmits apower to the power divider; the power divider transmits splits the powerinto some equal parts and transmits the equal power to each individualdelay path in the switchable phase delay module; according to thelocation of the radio frequency energy-harvesting apparatus, theharmonic radar control unit controls the switchable phase delay moduleto control a phase of the power, so that the radar wave beam of theradar wave transmitted from the antenna array is directed toward thelocation of the radio frequency energy-harvesting apparatus.
 5. Theradio frequency energy-transmitting apparatus in claim 4, wherein theharmonic radar control unit comprises: a harmonic radar control circuitelectrically connected to the switchable phase delay module; and alocation determination circuit electrically connected to the harmonicradar control circuit, wherein the harmonic radar unit furthercomprises: a harmonic receiving antenna; and a harmonic power detectorelectrically connected to the harmonic receiving antenna and thelocation determination circuit, wherein after the location determinationcircuit receives the radar reflection harmonic wave through the harmonicreceiving antenna and the harmonic power detector, according to acomparative result between an intensity of the radar reflection harmonicwave and an intensity of a background harmonic noise, the locationdetermination circuit determines whether the radio frequencyenergy-harvesting apparatus exists or not, to generate a location signalrelated with the location of the radio frequency energy-harvestingapparatus; the location determination circuit transmits the locationsignal to the harmonic radar control circuit.
 6. The radio frequencyenergy-transmitting apparatus in claim 5, wherein the harmonic radarcontrol unit controls the switchable phase delay module by an analogmodulation control mode.
 7. A radio frequency energy-harvestingapparatus applied to a radio frequency energy-transmitting apparatuswith a location detection function, the radio frequencyenergy-harvesting apparatus comprising: a direct current signalreceiving-processing unit; a rectification and harmonic generation unitelectrically connected to the direct current signal receiving-processingunit; and a radar wave receiving-transmitting unit electricallyconnected to the rectification and harmonic generation unit, wherein theradio frequency energy-transmitting apparatus transmits a radar wavescanning to a space; after the radar wave receiving-transmitting unitreceives the radar wave, according to the radar wave, the radar wavereceiving-transmitting unit generates an alternating current signal; theradar wave receiving-transmitting unit transmits the alternating currentsignal to the rectification and harmonic generation unit; therectification and harmonic generation unit generates a radar reflectionharmonic wave and a direct current signal; a frequency of the radarreflection harmonic wave is different from a frequency of the radarwave; the rectification and harmonic generation unit transmits the radarreflection harmonic wave to the radio frequency energy-transmittingapparatus through the radar wave receiving-transmitting unit; therectification and harmonic generation unit transmits the direct currentsignal to the direct current signal receiving-processing unit.
 8. Theradio frequency energy-harvesting apparatus in claim 7, wherein thefrequency of the radar reflection harmonic wave is an integral multiplefrequency of the radar wave.
 9. The radio frequency energy-harvestingapparatus in claim 8, wherein the frequency of the radar reflectionharmonic wave is a double frequency of the radar wave.
 10. The radiofrequency energy-harvesting apparatus in claim 9, wherein the radar wavereceiving-transmitting unit comprises: a matching circuit electricallyconnected to the rectification and harmonic generation unit, whereinafter the radar wave receiving-transmitting unit receives the radarwave, according to the radar wave, the matching circuit processes theradar wave by a matching process to generate the alternating currentsignal; the matching circuit transmits the alternating current signal tothe rectification and harmonic generation unit.
 11. The radio frequencyenergy-harvesting apparatus in claim 10, wherein the radar wavereceiving-transmitting unit further comprises: a first selection switchelectrically connected to the matching circuit; and a second selectionswitch electrically connected to the matching circuit and therectification and harmonic generation unit.
 12. The radio frequencyenergy-harvesting apparatus in claim 11, wherein the matching circuitcomprises: a harmonic optimization matching sub-circuit electricallyconnected to the first selection switch and the second selection switch;and an energy-harvesting optimization matching sub-circuit electricallyconnected to the first selection switch and the second selection switch,wherein if the direct current signal is less than a predetermined value,the first selection switch and the second selection switch arecontrolled, so that the harmonic optimization matching sub-circuitreceives the radar wave; if the direct current signal is greater than orequal to the predetermined value, the first selection switch and thesecond selection switch are controlled, so that the energy-harvestingoptimization matching sub-circuit receives the radar wave.
 13. The radiofrequency energy-harvesting apparatus in claim 12, wherein the radarwave receiving-transmitting unit further comprises: a radar wavereceiving antenna electrically connected to the first selection switch;and a harmonic transmitting antenna electrically connected to the secondselection switch and the rectification and harmonic generation unit,wherein the radar wave receiving antenna receives the radar wave andtransmits the radar wave to the matching circuit through the firstselection switch; the rectification and harmonic generation unittransmits the radar reflection harmonic wave to the radio frequencyenergy-transmitting apparatus through the harmonic transmitting antenna.14. The radio frequency energy-harvesting apparatus in claim 13, whereinthe rectification and harmonic generation unit is a bridge rectifier.15. The radio frequency energy-harvesting apparatus in claim 14 furthercomprising: a low pass filter electrically connected to therectification and harmonic generation unit and the direct current signalreceiving-processing unit; and a selection switch controllerelectrically connected to the low pass filter, the first selectionswitch and the second selection switch, wherein the selection switchcontroller controls the first selection switch and the second selectionswitch.
 16. The radio frequency energy-harvesting apparatus in claim 15,wherein the radar wave receiving antenna and the harmonic transmittingantenna are integrated as a dual-mode antenna.
 17. A radio frequencyenergy-transmitting method comprising: a. transmitting a radar wavescanning to a space; b. after a radio frequency energy-harvestingapparatus receives the radar wave, according to the radar wave, theradio frequency energy-harvesting apparatus generating a radarreflection harmonic wave, wherein a frequency of the radar reflectionharmonic wave is different from a frequency of the radar wave; c. theradio frequency energy-harvesting apparatus transmitting the radarreflection harmonic wave; d. after receiving the radar reflectionharmonic wave, according to the radar reflection harmonic wave,determining a location of the radio frequency energy-harvestingapparatus; and e. according to the location of the radio frequencyenergy-harvesting apparatus, controlling a radar wave beam of the radarwave directing toward the location of the radio frequencyenergy-harvesting apparatus.
 18. The radio frequency energy-transmittingmethod in claim 17, wherein the frequency of the radar reflectionharmonic wave is an integral multiple frequency of the radar wave. 19.The radio frequency energy-transmitting method in claim 18, wherein inthe step d further comprises: a harmonic radar unit scanning andrecording power intensities of a plurality of radar electric waves, andif the power intensity of the radar electric wave is greater than abackground harmonic power intensity a power predetermined value, theharmonic radar unit determining that the radar electric wave is theradar reflection harmonic wave.
 20. The radio frequencyenergy-transmitting method in claim 19, wherein in the step d furthercomprises: if the power intensity of the radar electric wave is notgreater than the background harmonic power intensity the powerpredetermined value, the harmonic radar unit determining that the radarelectric wave is not the radar reflection harmonic wave, and then theharmonic radar unit eliminating the radar electric wave.